An electric coil

ABSTRACT

An electrical conductor-dielectric laminate having an elongated electrically conductive strip and a dielectric web adhesively secured to the conductive strip. The adhesive securing the conductive strip to the dielectric is spaced inwardly from the transverse edges of the dielectric web. The dielectric web has nonplanar portions between the adhesive and the transverse edges to provide a restricted width. The dielectric web has a restricted width generally equal to the width of the conductive strip and an expanded width greater than the width of the conductive strip. An electrical coil wound from the electrical conductordielectric laminate having the expanded width dielectric web serving as an electrical insulator between adjacent conductive wraps of the coil.

ilnited tates patet 1191 Butcher [54] ELECTRIC CURL [75] Inventor: Louis M. Butcher, New Kensington,

[73] Assignee: Aluminum Company of America,

Pittsburgh, Pa.

[22] Filed: Sept. 10, 1971 [21] Appl. No.: 179,288

1451 Apr. 1a, 1973 Attorney-Arnold B. Silverman [5 7 ABSTRACT An electrical conductor-dielectric laminate having an elongated electrically conductive strip and a dielectric web adhesively secured to the conductive strip. The adhesive securing the conductive strip to the dielectric [52] 11.8. C1. ..336/206, 161/137, 174/1 17 FF, is spaced inwardly from the transverse edges of the 174/] 17 A, 336/232 dielectric web. The dielectric web has nonplanar por- [51 lint. C1. .1101? 27/32 tions between the adhesive and the transverse edges to [58] Field of Search ..336/206, 232, 205; pr vi e a restricted width. The dielectric web has a 174/113 R, 117 FF, 117 A; 161/133, 137; restricted width generally equal to the width of the 317/260 conductive strip and an expanded width greater than the width of the conductive strip. [56] References (med An electrical coil wound from the electrical conduc- UNITED STATES PATENTS tor-dielectric laminate having the expanded width dielectric web serving as an electricai insulator 1,278,993 9/1918 Parks ..336/206 between adjacent conductive wraps of the coil 3,246,271 4/1966 Ford ..336/206 x 3,474,370 10/1969 Lightner ..336/232 x 7 Claims, 6 Drawing Figures PATENTEU 1 01975 SHEET 2 OF 2 FIG. 4.

AN ELECTRIC con.

BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates generally to a method of manufacturing a laminated strip for use in electrical coils and, more specifically, it relates to the use of such strip in methods of automatically providing electrical insulation between adjacent conductive wraps so as to prevent undesired edge to edge shorting.

2. Description of the Prior Art It has been known to manufacture electrical coils by employing conductive strip materials wrapped in coil form with insulating materials interposed between adjacent wraps. Such coils are frequently used in capacitors, solenoids, transformers and the like. One of the difficulties encountered in manufacturing such electrical coils has been the need to provide insulating material of greater width than the conductive strip intermediate successive conductive wraps in order to prevent undesired edge to edge shorting. In the event that the dielectric webs were prelaminated to the conductor sheet prior to slitting into individual widths, bothplies would have anidentical width and effective insulating against undesired edge to edge shorting would not be provided. As a result it is necessary to use a wider dielectric web which has been separately fabricated. It has generally been the practice to manufacture such coils by first slitting the conductor tothe desiredfinalwidth and subsequently, during the actual coil winding, interleaving or inserting the wider dielectric in order to provide effective insulation against edge to edge shorting. This requires not only burdensome independent handling and feeding of the conductor and dielectric, but also requires aligning of the independent strips and coordination of feed rates. In addition, tensile fracture of the unsupported conductive strip during application of winding tensions caused disruptive and inefficient work stoppages. p

It has also been known to slit the conductor sheet into individual widths and to subsequently bond a wider dielectric theretoprior to coil winding.

It, therefore, has been necessary, in this type of coil manufacture, to employ inefficient methods involving first providing the'individual width conductive strips and subsequently providing the wider dielectric for each such strip in a separate stage of manufacture of the coil, either through interleaving during winding or lamination of an independent dielectric strip of greater width prior to winding. See generally U.S. Pat. Nos. 3,303,550 and 3,477,126.

Thereremains, therefore, a need for an effective means of coil fabrication which provides the desired electrical insulating characteristics and yet does not require inefficient, separate creation, handling and interleaving of the dielectric material.

SUMMARY OF THE INVENTION and the transverse edges of the dielectric web. In an alternate form, some or all of the nonplanar portions are loosely bonded to the conductive strip in such a fashion as to permit transverse expansion responsive to application of a compressive force. In this restricted width position the dielectric and the conductivestrip have generally identical transverse widths. The laminate is then placed in compression in order to effect a transverse expansion of the dielectric web to an expanded width which is greater than the width of the conductive strip. This may conveniently be accomplished during winding of the coils with the winding tension so established as to result in automatic sequential application of compressive force to successive laminate wraps to create transverse expansion of the dielectric web by reforming of some or all the nonplanar portions.

This method also contemplates the use of multiple width laminates having a dielectric web and conductive strip joined by bonding the strip and web longitudinally at a number of transversely spaced positions. The

dielectric web is provided with nonplanar portions in regions intermediate the adhesive sectors. The multiple width laminate may then be slit into a number of individual laminated strips each having an adhesive sector disposed at a position spaced inwardly from the transverse edges of the dielectric web with each web having a restricted width substantially equal to the width of the conductive strip. Subsequently applied compressive force results in the desired transverse expansion of the dielectric web.

The method of this invention produces an electrical conductor-dielectric laminate having an elongated electrically conductive strip and a dielectric web adhesively secured to the conductive strip by means of an adhesive which is spaced inwardly from the transverse edges of the dielectric web. The nonplanar portions of the dielectric web provide a restricted width which, in effect, creates a reservoir of material for transverse expansion when the longitudinal strip is placed in compression. This compressive force may conveniently be applied either during winding of the electrical coil or by an independent operation.

preferably has an expanded width of 3 to 25 percent greater than the width of the conductive strip. The amount of excess width is preferably related to contemplated electrical potential with respect to which the coil will be exposed, with increased width being employed with increasedelectrical potential in order to improve insulating characteristics.

It is an object of this invention, to provide a method of simply and effectively producing a laminated electrical coil employing a conductive strip and -a wider dielectric web which effectively insulates edges of adjacent conductive wraps of the electrical coil.

It is another object of this invention to provide such a method wherein the laminate may be produced with both plies of generally equal width and subsequent tensioning of the laminate during rewinding effectively sequentially compressing adjacent coil wraps to expand the dielectric web.

It is another object of this invention to provide such a method wherein the laminate may be prepared initially of normalcoil winding tension in order to provide ef-- fective. insulation of the edges of adjacent conductive wraps.

It is another object of this invention to produce a conductive metal strip laminate andthe resultant insulated coil in such a fashion as to make maximum use of conventional equipment while eliminating the need for separate handling and insertion or joinder of an insulating web.

These and other objects of the invention will be more 1 fully understood from the following description of the invention, on'reference to the illustrations appended v "BRIEF DESCRIPTION THE DRAWINGS showing a'form of nonplanar dielectric material contemplated by this invention. v n FIG. 2 is a" perspective view, partially broken away, showing one formof laminate of this invention during the process of slitting a multiplewidth member into individual laminate strips. 1 Q i FIG. 3 illustrates an electricalcoil of this invention having the adhe'sively bonded dielectric projecting transversely outwardly. I

FIG. 4 is a sectional view taken through 4-4 of FIG. 3 showing the insulation of adjacent conductive wraps of the coil;

FIG. 5 shows a modified form-of dielectric web contemplated by this invention.

FIG. 6 is a cross sectional illustration Referring now more specifically to FIG. 1, there is I shown a dielectric web 2 which has a leading end 4 and a pair of transverse'edges .6, 8. It is noted that the FIGLs lisa perspective view, partially broken away, I

verse expansion of the web to an enlarged width. In general, the expression will contemplate changes in direction of the web as it extends in 'a transverse direction and include bends or folds which have at least a component extending in a transverse direction, but will not contemplate mere variations in web thickness.

Referring now'to FIG. 2, there isshown a multiwidth laminate of this invention. The laminate has an undulating dielectric web 2 which is secured to a superposed electrically conductive metal strip 16, which is generally offoil or sheet thickness. The dielectric web 2 is adhesively bonded to the metal strip 16 by means of a number of adhesive sections 18'which are generally longitudinally directed and transversely spaced with respect to each other. The adhesive sections 18 are preferably, but not necessarily, longitudinally substantially continuous.

In a preferred form of this invention the metal strip 16 will be an electrically'conductive strip having a thickness ofabout 0.00014 inch to 0.010 inch. The smaller gauges are generally preferred for end uses such as capacitor coils, while the larger gauges are generally preferred for heavy duty transformers and the like. While numerous strip materials maybe employed, aluminum and copper are, among thepreferred materials because they are highly conductive and relatively inexpensive. H r p v I t With respect tothe dielectric web 2 one of the preferred materials is paper, such as impregnated natural kraft having a thickness of about 0.0003 to 0.005

taken through 6-6 of FIG. 5 and shows nonplanar portions of the dielectric web 2 has a plurality of undulating sections 10 which are transversely directed and define a plurality of longitudinal grooves 12. These undulating sections 10 provide a reservoir of material in the restricted widthdielectric web 2 which facilitate transverseex pansion to an enlarged width in a manner which will be described infdetail' below while for convenience of illustration referencegherein will be made'to a dielectric webj2 havingundulating sections.l0,',it will be ap prcciated'thatvarious forms of profile which provide for subsequent transverse expansion 'of restricted porterm nonplanar portions, and words of similar import, as used herein shall'refer to departures from a generally'planar, flat web profile, which departures reduce the transversewidth of the web and provide a reservoir'ofmaterial which facilitates subsequent transtions of the dielectric web 2 may be employed. The I inch. Also uniquely suited fo'ruse with thisinvention are a wide range of plastic tilrnsincluding polyethylene, polyester, vinyl, polyvinyl. chloride and polycarbonate having a thickness ofabout 0.00015 to 0.005 inch. The dielectric web 2 shown in FIGS. "land 2 may be a plastic material whichhasbeen provided with undula tions' in any convenient manner, such as by extrusion and/or formation between a pair of mated roller dies.

With respect to adhesives, any adhesive which will effectively bond the "two materials'at the desired predetermined locations and will not deteriorate under winding tensions and'exposu're to a wide range of atmospheric conditions is suitable. Typical of suitable materials are thermoplastics, such as polyurethane, vinyls, polyesters, polyamides and epoxies. I-Iot melt adhesives such as paraffin waxes, microcrystalline waxes, natural waxes and asphalt and coal based products may also be employed. Also suitable for use with certain dielectric materials are water based adhesives such as casein neoprenes, latexes, styrene butadiene rubber and polyvinylacetates. v

While it is important to establish the laminate of this invention by bondingthe conductive strip to the dielectric web in the manner described herein, it'will be appreciated that withsorn'ej combinations of materials this may be provided so long as the freedom of transverse expansion through displacement of nonplanar portions of the dielectric web is preserved.

Referring once again to FIG. 2, it is seen that the multiple width metal strip 16 is longitudinally severed at a number of locations by means of slitters 20 in order to establish a number of individual laminated strips having metal strips 16a to which are secured a number of dielectric webs 2a. It is noted that the adhesive is preferably applied generally transversely centrally of each individual metal strip 16a. The adhesive preferably covers less than about two-thirds of the surface area of the surface of the metal strip 16a to which web 2a is secured. This results in the restricted width dielectric web 2a having a substantially equal width to the individual metal strip 16a. This restricted width is provided by nonplanar portions in the form of undulating surfaces disposed intermediate the adhesive section 18 and the transverse edges 8, 6. Division by means of slitters 20 is effected at positions generally midway between adjacent adhesive sections 18. While the preferred form of this embodiment of the invention contemplates the use of generally centrally disposed substantially continuous adhesive sections 18, it will be appreciated that the invention is not so limited. Longitudinally discontinuous sections, for example, may be employed. Other patterns of adhesive which effectively secure the dielectric 2a to a metal strip 16a in such a fashion as to provide a strong, durable bond while establishing a restricted width dielectric web 2a with nonplanar portions being free to expand in a transverse direction in order to create an increased width may be employed.

An individual laminated strip of the type shown is subjected to compressive forces applied generally to exposed surfaces of the dielectric web 20 and metal strip 16a. As used herein, reference to compressive force" or compression and words of similar import as applied to the laminate shall refer to compressive force applied to opposed exposed surfaces of the laminate in such a fashion as to create compression and transverse expansion of nonplanar portions of the dielectric web. This is preferably accomplished by reduction'of the height of nonplanar portions of the dielectric web without appreciably reducing the web thickness through thinning of the material, as opposed to changes in direction of the web as it extends in a transverse direction. This compressively established transverse expansion serves to effect the desired expansion of the dielectric web Zn from its initial restricted width to an enlarged width'which is greater than the width of metal strip 16a without impairing the basic web strength. In general, it will be preferred for purposes of subsequent effective coil formation to have the transverse expansion effected in both transverse directions. One advantage of the present invention is that it not only eliminates the need for a separate step in coil fabrication involving the insertion of a dielectric, but also the desired transverse expansion may be effected by means of tension established during normal coil winding procedures. This tension creates compression of each coil wrap sequentially to expand the dielectric. As a result, one using the above described method need not establish any special procedures for handling the material of this invention or winding of coils therefrom. In fact, the use of the laminated strip of this invention reduces the likelihood of strip fracture during winding as a result of winding tension as compared with winding unbacked strip which is being interleaved with a dielectric during winding. Also, the laminate of this invention reduces the burden of obtaining proper alignment between the conductive strip and a separate dielectric during interleaving of the dielectric with successive wraps of a conductive strip.

In lieu of establishing transverse expansion of the dielectric web responsive to compressive forces established by winding tension created during coil formation, one might establish the transverse widening by an independent compressing operation, as by passing the laminated strip through a pair of mated rolls to establish compression. Also, rewinding the slit laminate strip, independent of and prior to coil formation, may be employed, if desired. The former approach is generally the most expeditious means of effecting expansion of the dielectric as it eliminates the need for independent processing steps.

Referring now to FIGS. 3 and 4, an electrical coil made by the method of this invention is illustrated. FIG. 3 shows a coil 22 having a plurality of wraps of the laminate consisting of a conductive metal strip 24 and a dielectric web 26. The outer ply 28 may be secured in place by a suitable retaining element (not shown). As is seen in the detailed illustration of FIG. 4, the dielectric web 26 has been secured to the metal strip 24 by means of an adhesive 30. It is noted that, as is preferred, the adhesive is generally centrally disposed and is spaced transversely inwardly from the edges of the expanded width dielectric web 26. It is seen that the width of the expanded dielectric web 26 exceeds the width of the metal strip 24 and projects transversely outwardly beyond each edge 32, 34 of the metal strip 24. This distance is sufiicient to provide electrical insulation between adjacent wraps of the metal strip 24 so as to prevent undesired edge to edge shorting. In the preferred form, the expanded dielectric web 26 will have a width of about 3 to 25 percent greater than the width of the metal strip 24.

Referring now to FIGS. 5 and 6, another form of dielectric web contemplated by this invention will be considered. This form of dielectric web is a crepe paper which may be formed in the conventional fashion. The dielectric web shown in FIGS. 5 and 6 is generally unsymmetrical. It has random orientation of the non planar portions provided by a multiplicity of folds 36 having various orientations, depths and lengths. The profile of a sampling of these folds 36 is shown in FIG. 6. This type of dielectric web is employed in the same fashion as the above described dielectric web in that it is adhesively bonded to a superposed conductor strip in such a fashion as to provide nonplanar portions in the space intermediate the adhesive and the transverse edges 38, 40. In a preferred use of this dielectric web, the web will have adhesive bonding provided in the region A and will have unbonded sectors B, C. It is preferred that the region A be less than two-thirds of the transverse width of the conductor strip to which the dielectric web will be secured.

EXAMPLE In order to illustrate the manner in which the present invention may'be employed, an example will be considered. An aluminum foil material having a thickness of about 0.002 and a width of about 30 inches is coated with 28 continuous longitudinal ribbons of adhesive by any convenient means such as gravure rolls. These ribbons of adhesive are spaced about one inch from each other with the transverse outermost ribbons being spaced about one half inch from'the edges of the foil material. An impregnatednatural kraft paper having a thickness of about 0.0005 inch is provided with nonplanar portions establishing a restricted width of about 30 inches and is laminated to the aluminum foil by means of the adhesive. The laminated material is subsequently slit longitudinally to provide a number of elongated laminatedstrips one inch wide having the adhesive joinder effected generally centrally and unbonded regions on alternate sides of the adhesively bonded portions. The individual laminated strips are then subjected to winding tension either in placing them on rewind reels or in winding them into the ultimate coil structure. The winding tension creates compressive force on each wrap of the laminate as it is wound on the coil. This produces a transverse expansion of the dielectric web in both directions in order to establish the desired expanded width for the dielectric.

In the embodiments of the'inventio'n described above freedom of transverse expansion through deformation of the dielectric web has been preserved by providing effective bonding of the dielectric web to the conductive strip, while preserving unbonded nonplanar portions intermediatethe bonded section and .the transverse edges of the dielectric. In another embodiment of this invention the laminate may be established with loose bonds between the dielectric web and conductive strip with bonding being effected between substantially all nonplanar portions-of the dielectric web and the conductive strip. The term loose bond and words of similar import as used herein shall refer to adhesive or self-bonded joinder of the dielectric web to the conductive strip in such a fashion as to permit transverse expansionof some or all of the nonplanarportions of the dielectric web responsive to application of a compressive force to the laminate. While such loose bonds may be provided in the central transverse portions of the laminate and/or in the transversely outwardly disposed nonplanarportions, it is preferred to provide such loose bonds substantially continuously across the width of the laminate, with or without longitudinal continuity.

As the nonplanar portionsof the dielectric web will bring portions of the web out of contact with the conductive strip, the term continuous as used in this context shall refer to bonding between those portions of the dielectricwhich are initially in surface to surface contact with the conductive strip and will not require bonding of those portions which are not in such contact. When the bond is effected across the entire width of the laminate in this fashion, it will be deemed to be transversely continuously bonded regardless of the a presence or absence of. longitudinal continuity of the bond.

The. usev of continuous adhesive advantageously eliminatesthe need for special patterned adhesive applicators and/or bonding apparatus. Also, the need for Loose bonds between the dielectric web and the conductive strip may be obtained by the use of hot melt adhesives such as microcrystalline wax or'other asphalt or coal tar based adhesives. In addition, pressure sensitive adhesives may be employed to obtain effective joinder of the two laminate plies whilepreserving the desired freedom of transverse expansion. In addition to the use of various other types of adhesives, useof the dielectric web to provide a self-adhered bond may be employed.

Transverse expansion of dielectric portions of laminates effected by loose bonding is obtained in essentially the same fashionas with other embodiments of this invention.

In effecting transverse expansion of the dielectric web of laminates of this invention compressive force is applied to the laminate. This force may beconsidered as being applied to a horizontally oriented laminate, for example, by vertical forces applied in a relative closing direction to exposed upper and lower surfaces of the laminate. This willproduce an unfolding or transverse expansion of the restricted width dielectric web. In a preferred form, this expansion is obtained during laminate winding as a result of the longitudinal winding tension causing each succeeding wrap of the laminate to exert a compressive .force on the previous wrap to flatten the nonplanar portions and transversely enlarge the restricted width dielectric web to the desired expanded width. The tension which must be applied in order to establish the desired expansion is a function of the amount of transverse expansion desired and the extent'to which the nonplanar portions depart from the general plane of the dielectric web. The tension applied cannot be more than the ultimate tensile strength of the laminate. There is no absolute minimum tension required as it has been found that conventional winding tensions are more than adequate to establish sufficient compressive force to effect a minimum desired transverse expansion of the dielectric to prevent undesired edge to edge shorts. In general, it is preferred to provide a minimum tension of about one-half pound per mil inch of width of dielectric web. The term mil inch refers to the thickness of the dielectric web in mils multiplied by the width of the dielectric 'web in inches.

It will, therefore, be appreciated that the method and resultant product of this invention produce a means of effectively establishing a laminatedmaterial' wherein the conductive strip has .a first width and an adhesively bonded superposed dielectric web has. an expanded width greater than that of the conductive metal strip. This is accomplished without the needy fora separate operation which either laminates a wider dielectric strip to the conductive strip or requires interleaving of a dielectric material. All of this is accomplished by providing a laminate which has certain portions of the conductive strip bonded to a'dielectric web. The dielectric web has nonplanar portions, at least in the regions intermediate the adhesive and the transverse edges of the dielectric. In another form of the invention, a loose bond permits a substantially continuous bond between the dielectric web and conductive strip. The transverse expansion may economically be effected by application of a compressive force either as a separate operation or during normal winding procedures in an automatic fashion and may preferably be accomplished during electrical coil winding.

While for purposes of simplicity of illustration the conductive strip has been shown as being disposed above a generally horizontal underlying dielectric web, it will be appreciated that relative orientations of the laminate plies during securement and force application are illustrative and all that is required is that the strip and web be secured in the desired position of generally surface to surface superposed adjacency, without regard to orientation of the laminate or which material overlies the other during laminate formation and force application.

Whereas particular embodiments of the invention have been described above for purposes of illustration, it will be evident to those skilled in the art that numerous variations of the details may be made without departing from the invention as defined in the appended claims.

lclaim: 1. An electrical conductor-dielectric laminate comprising an elongated electrically conductive strip, a superposed dielectric web adhesively bonded to said conductive strip,

said adhesive bonding said conductive strip to said dielectric web spaced inwardly from at least one transverse edge of said dielectric web, said dielectric web having nonplanar portions between said adhesive bond and said transverse edges providing a restricted width for said web, and

said dielectric web having a restricted width generally equal to the width of said conductive strip and an expanded width greater than the width of said conductive. strip, whereby placing said laminate in compression will establish transverse expansion of said nonplanar portions of said dielectric web to create a greater dielectric web width than said conductive strip width.

2. The electrical conductor-dielectric laminate of claim 1 including said dielectric web having a substantially longitudinal said conductive strip havinga number of transversely spaced longitudinal adhesive sections disposed intermediate the transverse edges thereof, and

said adhesive sections so spaced as to permit slitting of said conductive strip to divide said conductive strip into a number of elongated laminates having dielectric webs secured thereto with nonplanar portions adjacent the transverse edges of said conductive strip being unbonded, 4. The electrical conductor-dielectric laminate of claim 2 including said adhesive bond is generally transversely centrally disposed on said conductive strip, and said adhesive bond covers less than two-thirds of the surface area of the surface of said conductive strip to which said dielectric web is secured. 5. The electrical conductor-dielectric laminate of claim 4 including said conductive strip is metal,

said metal strip has a thickness of about 0.00014 to 0.010 inch, and said dielectric web is selected from the group consisting of plastic film having a thickness of about 0.00015 to 0.005 inch and paper having a thickness of about 0.0003 to 0.005 inch. 6. A laminated electrical coil comprising a coiled elongated electrically conductive strip, a dielectric web generally aligned with and longitudinally bonded to said conductive strip, said dielectric web projecting transversely beyond both edges of said conductive strip, said transversely projecting portions of said dielectric web having nonplanar portions formed therein, and said bonding established at a position spaced inwardly from the transverse edges of said conductive strip. 7. The laminated electrical coil of claim 6 including a substantially continuous generally longitudinally directed adhesive bond disposed substantially transversely centrally of said conductive strip, and said dielectric web having a width of about 3 to 25 percent greater than the width of said conductive strip.

t 4 F t 

1. An electrical conductor-dielectric laminate comprising an elongated electrically conductive strip, a superposed dielectric web adhesively bonded to said conductive strip, said adhesive bonding said conductive strip to said dielectric web spaced inwardly from at least one transverse edge of said dielectric web, said dielectric web having nonplanar portions between said adhesive bond and said transverse edges providing a restricted width for said web, and said dielectric web having a restricted width generally equal to the width of said conductive strip and an expanded width greater than the width of said conductive strip, whereby placing said laminate in compression will establish transverse expansion of said nonplanar portions of said dielectric web to create a greater dielectric web width than said conductive strip width.
 2. The electrical conductor-dielectric laminate of claim 1 including said dielectric web having a substantially longitudinal portion bonded to said conductive strip, and said dielectric web having a restricted width cross sectional profile provided with a number of undulations defining a number of longitudinal folds.
 3. The electrical conductor-dielectric laminate of claim 1 including said conductive strip having a number of transversely spaced longitudinal adhesive sections disposed intermediate the transverse edges thereof, and said adhesive sections so spaced as to permit slitting of said conductive strip to divide said conductive strip into a number of elongated laminates having dielectric webs secured thereto with nonplanar portions adjacent the transverse edges of said conductive strip being unbonded.
 4. The electrical conductor-dielectric laminate of claim 2 including said adhesive bond is generally transversely centrally disposed on said conductive strip, and said adhesive bond covers less than two-thirds of the surface area of the surface of said conductive strip to which said dielectric web is secured.
 5. The electrical conductor-dielectric laminate of claim 4 including said conductive strip is metal, said metal strip has a thickness of about 0.00014 to 0.010 inch, and said dielectric web is selected from the group consisting of plastic film having a thickness of about 0.00015 to 0.005 inch and paper having a thickness of about 0.0003 to 0.005 inch.
 6. A laminated electrical coil comprising a coiled elongated electRically conductive strip, a dielectric web generally aligned with and longitudinally bonded to said conductive strip, said dielectric web projecting transversely beyond both edges of said conductive strip, said transversely projecting portions of said dielectric web having nonplanar portions formed therein, and said bonding established at a position spaced inwardly from the transverse edges of said conductive strip.
 7. The laminated electrical coil of claim 6 including a substantially continuous generally longitudinally directed adhesive bond disposed substantially transversely centrally of said conductive strip, and said dielectric web having a width of about 3 to 25 percent greater than the width of said conductive strip. 